This is a thing that I like

"Snuze: Needs another Swede" (markg) 02/06/2015 at 00:07 • Filed to: None

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I absolutely love reversed heads/center exhaust. I cant help but think that this could be recreated using a commonly available Ford 4.6L Mod motor.

Cherry_man1 > Snuze: Needs another Swede 02/06/2015 at 00:11

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DUDE GT40 Kit car with a Mach 1 Motor.

Jedidiah > Snuze: Needs another Swede 02/06/2015 at 00:11

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Cadillac monobloc style

Snuze: Needs another Swede > Cherry_man1 02/06/2015 at 00:12

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I'd go one better... Lotus 38 Replica

Cherry_man1 > Snuze: Needs another Swede 02/06/2015 at 00:15

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Imagine if someone were to work a Termi motor like that.....

Snuze: Needs another Swede > Cherry_man1 02/06/2015 at 00:24

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That would be so badass!

When I have the space to work, I'd like to pick of a SOHC Mod, you can get them with a spun bearing or something for < $100. And I just want to see if it can be done. I've found coolant and oil flow path diagrams for the Mod, and I think with a little machining of the block/heads it can be done. And I think around 400HP could be quite doable. I think a nice Lotus 38 replica, or vintage style F1 car of the same era would come in at around 1200lbs. With 400HP, thats like having a Corvette with north of 1000HP - it would be an absolute handful.

Jordan and the Slowrunner, Boomer Intensifies > Snuze: Needs another Swede 02/06/2015 at 00:28

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Ford actually makes an engine currently with center exhaust manifolds... It's just a heavy diesel with a fuckton of power.

Birddog > Snuze: Needs another Swede 02/06/2015 at 00:33

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Look up Buick Nailhead reverse flow.

Cherry_man1 > Snuze: Needs another Swede 02/06/2015 at 00:34

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No PS and no PB either.

bryan40oop > Snuze: Needs another Swede 02/06/2015 at 00:46

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"I cant help but think that this could be recreated using a commonly available Ford 4.6L Mod motor"

Wouldn't it be much easier to use a pushrod engine? yah know, timing chains.

saabstory | fixes bikes, breaks cars > Snuze: Needs another Swede 02/06/2015 at 02:43

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But with a nicer chassis, hopefully! Sounds sweet though.

jdrgoat - Ponticrack? > Snuze: Needs another Swede 02/06/2015 at 03:25

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Look into the valves a little more. I've heard of a Cadillac Northstar being converted to reverse flow, but they also mentioned that the intake and exhaust valves are the same size on the N*. I don't think that's the case for most engines.

Snuze: Needs another Swede > Cherry_man1 02/06/2015 at 08:55

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Definitely no PS. PB I'm on the fence about, but in a light car like that you can probably get away with not having it.

Snuze: Needs another Swede > saabstory | fixes bikes, breaks cars 02/06/2015 at 08:57

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Yeah. I've got some ideas floating around in my head. And there's the guy that does the F1-67 kit cars. He's got some good chassis pictures online, I like what he's doing a lot.

I also know some people that do some great carbon fibre work, so I may consider doing a monocoque chassis just for fun. But that's a ways off. I want to get the engine working first, but that wont happen for at least a year - that's the wife and I's timeline for house buying.

Snuze: Needs another Swede > Jordan and the Slowrunner, Boomer Intensifies 02/06/2015 at 09:00

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Yeah, I've seen that. BMW does it too in the twin turbo gas V8's in the X5/X6. And I think there's a Bentley V8 that does it too.

But I think you can accomplish it with a Mod motor and some creative machining. And I'm pretty sure I could go buy a Mod motor, do the machining, get a set of Trick Flow heads, race cams, valves and springs, and rebuild the bottom end, all for less than what it would cost to get my hands on a BMW motor. Plus they are turbo, so to de-turbo it (because a vintage F1 would need to be N/A) would be a pain in the ass.

Snuze: Needs another Swede > bryan40oop 02/06/2015 at 09:07

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I think it would actually be harder. You can't physically swap the heads bank to bank, because there's nowhere for the pushrods to go. I have seen people change up the cam (I don't know if you run it 180 degrees or if its a custom grind, or what) but you can basically work the valves backwards, so your intakes become your exhaust and vice versa.

The problem with doing this is, while it's novel and strange, from a performance standpoint it sucks. The exhaust valves are almost always much smaller than your intakes. So when switched, you have very small intake valves that choke flow, and very large exhaust valves and ports that are going to kill velocity and hurt cylinder scavenging.

Also, what most people don't realize is, Ford only makes 1 cylinder head casting, at least on the SOHC mod motors. So you can swap the head from one side to the other, you just have to spin it 180 degrees. Which is part of the reason why I think flipping the heads may work - upon initial inspection (i.e. I've looked at a lot of internet pictures) the bolt holes and coolant passages line up. The problems are the oil feeds and returns, but I have some ideas on how to make that work.

Snuze: Needs another Swede > Jedidiah 02/06/2015 at 09:14

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That is a sexy, sexy motor. And a lot of guys actually flip intake and exhaust on Flat heads. The Fords had 4 intake ports but only 3 exhaust ports - they center 2 cylinders in each bank shared a port. For everyday applications when they only made like 85HP, it was fine. But people racing them found that with a lot of extra compression and fuel and air, it would burn up exhaust valves on those center cylinders like crazy.

So guys started swapping ports, running the headers out the center of the Vee so each exhaust had its own port. And you could run 3 side draft carbs on each side, it didn't really matter about the center port as much because only one of the 2 cylinders was going to be drawing in air/fuel at any given time, so there were no carb/fueling issues. I think the old flaties also had about the same size intake and exhaust valves (nevermind that it's a flat head an the port geometry is about the worst thing in the world) so you didn't have the velocity/scavenging issues that you would have doing this on a more modern OHV or OHC motor where the intake is significantly larger than the exhaust.

Snuze: Needs another Swede > Birddog 02/06/2015 at 09:16

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I think I've seen that before, but I will have to do some digging. I wonder if they actually swap heads, or they just switch ports up (intakes become exhaust, and vice versa). I'm trying to avoid that because its an awful performance solution because the intake and exhaust valves are different sizes, so you suddenly wind up with too small intake ports, and exhaust ports which are way too big and that kills velocity/scavenging.

All that said, I do love nailheads.

Snuze: Needs another Swede > jdrgoat - Ponticrack? 02/06/2015 at 09:19

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The guy (can't remember his name) did it for the Splinter, the wooden supercar. I actually e-mailed him one day to ask about it, try and pump him for some technical details. All I got back was "It was the biggest pain in the ass in the world. I highly suggest you don't even try it."

However, it doesn't look that bad, I think it might even work. But I suspect I can get a Mod motor way cheaper, and I've found coolant and oil flow diagrams for the Mod so I have a pretty good idea already of exactly what the issues are going to be, and have some ideas on how to solve them. I can't find info like that for an N*, and with the 1 person I've seen do it not really being helpful, its basically uncharted territory.

Cherry_man1 > Snuze: Needs another Swede 02/06/2015 at 11:59

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maybe but pb to me is s must

Snuze: Needs another Swede > Cherry_man1 02/06/2015 at 12:25

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Yeah, true, it might be a good thing to have. Its a light car but also a fast car, so a lot of clamping force is probably a good idea.

Law > Snuze: Needs another Swede 02/06/2015 at 15:38

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BMW S63B44 variants used in F10 M5, X5M, X6M also have reverse flow heads

Snuze: Needs another Swede > Law 02/06/2015 at 15:42

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Yup! I just learned that last night as I was hunting for information on this topic. It's a great idea but I don't think it would work out well in reality. Being that they are used predominantly in M cars, they are going to be obscenely expensive. And I really would only want to make about 400HP, and I don't want turbos so I can have a nasty snake bundle exhaust back there. De-turboing them and reworking them to make NA power would be a huge chore - need new pistons to raise compression, new cams and valve springs to allow it to rev up and shift the powerband, and completely retune the fuel and timing curves since theres no more hair dryers. And everything would have to be custom since no one in their right mind would ever do that sort of thing to this engine.

saabstory | fixes bikes, breaks cars > Snuze: Needs another Swede 02/06/2015 at 18:48

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That's going to be amazing. Hopefully we'll both still be on Oppo then so I can see your kickass project!